At the moment, our colleagues in the southern hemisphere are in the middle of their summer Sporadic-E season and there are of course plenty of openings on the VHF bands.
On the 12th of December 2020, there was a remarkable opening on 6-metres between Australia and South America. For example, the map below from the PSK Reporter website shows the sent/received reports for VK3BD in the SE of Australia.
What is truly remarkable about this is the sheer distance and the path of the signals.
For many, the distance between the stations in Australia and the stations in Brazil, Bolivia and Paraguay was in excess of 13,000 kms!
To put that into perspective for European readers, the distance from say the UK to Japan is about 9500 kms. Every year, there seems to be multi-hop Sporadic-E openings from Europe to Japan on 50 MHz which cause a lot of excitement. This opening from Australia to South America was significantly further.
The second interesting point was the path. In some instances, the Great Circle path crossed part of Antarctica with the most southerly path going as far as 78 degrees south. Again to put that into perspective for European readers, 78 degrees is about as far north as say the island of Svalbard to the north of Norway.
Far northern or far southern latitudes are not areas normally associated with Sporadic-E.
To get a view from the South American side, I took a screenshot of the map for CP6UA in Bolivia.
As the map shows, the stations in New Zealand (ZL) were also getting in on the action and the distance to them was an impressive 11,000 kms or so.
Mode of propagation???... The million dollar question. I presume it was multi-hop Sporadic-E but it was a lot of hops! One of the longest paths that I saw was between VK5BC and PT9FD, a distance of 13,530 kms.
VK5BC PT9FD 6m JT65 13530 km 22:17:50
The maximum distance for one Sporadic-E hop is about 2300 kms. Was it six hops of 2255 kms? Seven hops of 1933 kms? If it was multi-hop Sporadic-E then a lot of patches of Sporadic-E had to line up in a row and at the correct distance for it to work.
Addendum... Someone suggested that Polar Mesospheric Summer Echos (PMSE) with electrons gathering around ice crystals may have been responsible for this opening. I include it here for reference reference.
Contacts... I'm sure many contacts were made but the purpose of this post is just to highlight the fact that the opening occurred.
Looking at the PSK Reporter website, these were the stations that I saw listed...
VK3OT, VK3BD, VK3DUT, VK3OER, VK3WE, VK3KU
VK5PW, VK5BC, VK5PJ, VK5RM
Brazil - PY5HOT, PT9FT, PY5KD, PY5EK
Paraguay - ZP5DPC, ZP4KFZ
Bolivia - CP6UA
Argentina - LW2DAF, LU3CQ, LU9DO
Chile - CE3SX, CA3SOC, XQ3MCC
Uruguay - CX6DRA
DX-Cluster... Here are a selection of spots from the DX-Cluster...
PT9FD 50276.0 VK3OT 22:19 12 Dec JT65A GG27OR <> QF12ag TU 73 Australia
PT9FD 50276.0 VK5BC 22:00 12 Dec JT65A gg27or PF95jj tks 73 Australia
CE3SX 50276.0 VK5PJ 22:00 12 Dec FF46<>PF95MK TU Peter Australia
CP6UA 50276.0 VK3DUT 21:35 12 Dec Thanks New One Norm. 73 Australia
PY4AQA 50276.0 VK4QG 22:18 10 Dec JT65A -24 dB Australia
VK3OER 50276 PT9FD 23:24 12 Dec 20 JT65 -25 CQ Brazil
VK3OT-@ 50277.3 PT9FD 22:18 12 Dec 20 QF12ag GG27 jt65 qso 73 Brazil
VK3OT-@ 50277 PT9FD 22:14 12 Dec 20 cq pt9fd gg27 jt65a -19 Brazil
VK3OT-@ 50277 PY5HOT 21:42 12 Dec 20 cq gg46 jt65a Brazil
VK3OT-@ 50279 PT9FD 21:34 12 Dec 20 jt65 cq -23 Brazil
VK3OT-@ 50277 ZP4KFX 20:55 12 Dec 20 wow thanks JT65A Paraguay
VK3OT-@ 50277 ZP5DBC 20:50 12 Dec 20 JT65A thanks -19 Paraguay
I also kept a record for some of the Australian stations logs of the signals that they heard from South America for this opening. PSK Reporter normally wipes all records after 24 hours so it's nice to have some record of the opening. See below...